METAL-ION DEPENDENT REACTIVITY OF 2-(2'-THIENYL)PYRIDINE (HTHPY)

The reaction of 2-(2'-thienyl)pyridine (Hthpy) with palladium acetate results in a clean conversion to the mu-acetato-bridged dimeric cyclometallated complex [(thpy)Pd(mu-OAc)Pd(thpy)] in which a new Pd-C bond is formed at the 3' position of the thienyl ring. In contrast, treatment with Na[AuCl4] under similar conditions only results in the formation of the complex [(HL)AuCl3] in which the ligand acts as a monodentate N-donor. At higher temperatures the reaction of Na[AuCl4] with Hthpy yields a complex mixture of products, including complexes of 2-(5'-chloro-2'-thienyl)pyridine and 5,5'-bis(2-pyridyl)-2,2'-bithienyl. Independent syntheses of these latter compounds have confirmed their identities. The reaction of 2-(2'-thienyl)pyridine with [Ru(bpy)2Cl2] (bpy = 2,2'-bipyridine) in the presence of a chloride ion abstractor yields salts of the cation [Ru(bpy)2(Hthpy)]2+ which contains a bidentate N,S-bonded ligand.